Apparatus for closing a foil packing, in particular a foil bag

ABSTRACT

An apparatus for the heat-sealing of a film package, particularly a film bag, containing an article to be packed, which comprises a film-pulling device and a heat-sealing device defining a heat-sealing plane. A pair of pulling rollers is disposed adjacent the heat-sealing device on both sides of the heat-sealing plane. A device is provided for rotation of the pulling rollers and the latter are arranged for movement towards one and other.

United States Patent Timmerbeil 1 Feb. 18, 1975 [5 1 APPARATUS FORCLOSING A FOIL 3,200.560 8/1965 Randall 53/112 8 x CKI IN PARTICULAR AFOIL BAG 3.289.387 12/1966 Stagmeier et a1. 53/112 B 3.377.772 4/196853/372 x [75] In nt r: Kar -E ns Tlmmerbell, Ennepetal. 3,461.645 8/1969Synder 53/373 x Germany 3.471.991) 10/1969 Bonuchi et a1 53/372 X 3 731Assignee: Firma Packautomatic GmbH & C0. Wm 53/37 X Ennepetal GermanyPrimary E.\11miner-'l'ravis S. McGehee [22] Filed: Aug. 16, 1973Assistant lzxaminerHorace M. Culver Attorney, Agent. or FirmErnest G.Montague; Karl [21] Appl' 388311 F. Ross; Herbert Dubno [30] ForeignApplication Priority Data [57] ABSTRACT Aug. 19. 1972 Germany 2240909 Anapparatus for the heat-sealing of a film package, particularly a filmbag, containing an article to be [52] US. Cl. 53/373 packed, whichcomprises a film-pulling device and a [51] Int. Cl..... B65b 7/06, B65b13/22, B65b 51/14 heat-sealing device defining a heat-sealing plane. A[58] Field of Search 53/372, 373, 124 A, 124 B, pair of pulling rollersis disposed adjacent the heat- 53/24, 39, 40 sealing device on bothsides of the heat-sealing plane. A device is provided for rotation ofthe pulling rollers [56] References Cited and the latter are arrangedfor movement towards one UNITED STATES PATENTS and Other- 2,877,6153/1959 Foster 53/112 B X 6 Claims, 9 Drawing Figures PATEHTED FEB l 8I975 SHEET 1 BF 3 APPARATUS FOR CLOSING A FOIL PACKING, IN PARTICULAR AFOIL BAG package wrapping produced from? film irfwhiclfall sides of thepackage, except a single end side, are already closed to form a film bagwhich then is closed completely.

For this purpose prior-art devices include a heatsealing device and,behind this device, clamping and pulling jaws which are relativelymovable vertically so as to grip the overhanging film and then pull ithorizontally into an adjacent position by a horizontal movement, therebytightening the film against the material to be packed, whereupon theheat-sealing takes place. Devices of this type, have the disadvantagethat, because their parts move in two planes, they are rather expensiveto manufacture also it is not possible with these prior devices toobtain close and dependably tight packings around the goods. For thisreason, it frequently happens in practice that workers stand at theheat-sealing device in order to pull the protruding parts of the film byhand away from the goods and then tightly around the same so as toensure tight packaging.

It is therefore another object of the present invention to provide adevice of simple construction by means of which film-bag package, whichtightly hug the material to be packed can be obtained in an economicaland dependable manner.

According to a feature of the present invention l provide in thevicinity of the heat-sealing device a pair of pulling rollers, thepulling rolls of which are driven and are arranged on opposite sides ofthe heat-sealing plane, the rollers being movable with respect to eachother. The pair of pulling rollers provided in accordance with thepresent invention can now grip the protruding parts of the film bags andpull them along the article being packed which is held back (retained),for instance, by the pulling rolls themselves or other retaining means.In this way the tight package is always obtained, and even articles tobe packed which are of different height or of different depth can bepacked equally dependably and well.

Because a driven pair of pulling rollers is used in the system of thepresent invention, only movement in a single plane is necessary fortheir action and the drawing ofthe film. As a result, a considerablesimplification in construction is obtained, by comparing with a devicehaving clamping and pulling jaws which are movable in two planes atright angles to each other.

When the heat-sealing device is formed of two heatsealing jaws which aremovable towards each other, one pulling roller is arranged on the oneheat-sealing jaw and is movable together with it, while the otherpulling roller is arranged for movement by means of a swinging devicewhich is'provided on the fixed stand of the heat-sealing apparatus.

This arrangement of the pulling rollers is advantageous because thefirst pulling roller is movable directly with a heat-sealing jaw andthus does not require any drive of its own, while the other pullingroller is movable independently of the second heat-sealing jaw by aseparate swinging device. Preferably, the unheated heat-sealing jaw isprovided with the pulling roller which is movable with it, while theseparately swingable pulling roller is disposed adjacent the heatedheatsealing jaw. The latter arrangement has the advantage, that thepulling rollers can come into engagement and into active positionsbefore the film is heated by the heat-sealing jaw and, as beforepremature heat sealing. Despite the simplicity of design and low costcoupling one of the two pulling rollers with one of the two heatsealingjaws, the present invention provides a control of the pulling rollerswhich is independent of the movement of the heat-sealing jaws.

In accordance with another proposal of the present invention, the secondpulling roller, which is not connected with the heat-sealing jaw canalso be fixed in space within the region of the heat-sealing plane. Thisis advantageous, when flat bags are to be closed, rather than high filmbags or film bags of different height. ln the case of small, flat bags,the protruding film lies approximately in the heat-sealing plane, sothat it is sufficient for it to be grasped by the pulling roller, whichis movable with the first heat-sealing jaw and pressed against thefixedly positioned second roller. Thus no operating mechanism isrequired for the control movement of the pulling roller.

Depending on the nature of the goods to be packed and depending onwhether the bags produced are thin envelope-like containers or thickcushion like packings, the pulling rollers can be arranged eitherbetween the material to be packed and the heat-sealing jaws, or elsealong the side of the heat-sealing jaws facing away from the material tobe packed.

When the pulling rollers are arranged between the packaged article andthe heat-sealing jaws there is the substantial advantage that only anextremely slight projection of film is necessary in order for the filmto be gripped by the pulling rollers, and the amount of film requiredand the waste can therefore be reduced. When the pulling rollers arearranged behind the material being packed and behind the heat-sealingdevice, there is the advantage that extremely tight package can beproduced, since the heat-sealing takes place directly on the articlebeing packed. The material being packed can, in this case,advantageously rest against the heatsealing jaws while the film is beingpulled tight along it on all sides.

It is also advantageous, in accordance with the present invention, forthe drive of the first pulling roller to be an electric motor and forthis motor to drive the other pull roller in the cooperating position ofthe pair of pulling rollers by means of gears, at least one gear beingprovided on one side of each pulling roller.

Thus the two pulling rollers are driven synchronously when they restagainst each other and pull the film tight, while only a single driveunit is necessary for this purpose.

If the horizontal side surfaces of the sheet of packing film are alreadycompletely folded during the folding and packaging process which haspreceded the last heat-sealing, then it is advisable to provide a guideledge which extends in the direction of the folded side surfaces of thefilm packing and rests tightly against the material being packed. Thisguide ledge provides assurance on the one hand, that the folded sidesurfaces of the packing will remain folded and will not get in the wayof the final heat-sealing process; the guide ledge also provides anabutment for the material being packed as support against the pull ofthe film and thereby permits a deep bagging of the material beingpacked.

If, in accordance with a further feature of the present invention, thesurface of the lower pulling roller has a higher coefficient of frictionthan the surface of the upper pulling roller does it being assumed thatthe heat-sealing takes place in a horizontal plane this offers theadvantage, that even heavy materials can be packed dependably and withuniform tightness. The stronger pulling force on the lower sheet of filmas compared with the weaker pulling force on the upper sheet of filmwhich is necessary particularly when packing heavy articles in a filmpacking which rests snugly on all sides, is compensated for by thegreater friction force of the film against the lower pulling roller.

The lower pulling roller can be provided with a rougher covering orother known friction-increasing means. For instance, the lower rollercould be covered with soft Moltopren, while the upper roller is providedwith a covering of PVC, which has a lower coefficient of friction thanthe Moltopren covering. A uniform pull is obtained since the upperpulling roller slides on the upper film when certain pulling forces areexceeded, while the lower pulling roller still entrains the lower filmuntil a predetermined load has been reached.

The establishing of the predetermined load can be achieved by making themaximum torque of the motor driving the pulling rollers adjustable. Inorder to limit the torque, one can utilize overload switches or slipclutches or else select a suitable motor. By the limiting of the torqueor pulling force, overstretching or tearing of the film is reliablyprevented.

The present invention has thus succeeded in providing a device for theclosing of a film package, particularly a film bag, which is capable ofpushing material to be packed with adjustable force as deep as possibleinto a film sleeve. In addition, the present invention makes it possiblefor the film to be stretched as tightly as possible around the articlebeing packed. And finally 'packages of different depth of contents canbe closed while retaining the advantage of a tight, close packing.

It is immaterial in principle in this connection how the film bag whichis finally to be closed has been produced in a previous packagingmachine. The device can be used wherever it is desired to close a filmbag which is already closed on three sides.

These and other objects will become more readily apparent from thefollowing detailed description, reference being made to the accompanyingdrawing, in which:

FIG. 1 is a side-elevational view of a device in accordance with thepresent invention at the start of the closingprocess;

FIG. 2 an end view thereof;

FIG. 3 a top-plan view thereof;

FIGS. 4 to 6 are views corresponding to FIGS. 1-3, respectively at amore advanced stage of the closing process; and

FIGS. 7 to 9 are corresponding views in the final stage of theheat-sealing process.

It is immaterial how an article 10 to be packed has been brought into afilm bag bya previous packaging device or how this film bag has beenformed around the article to be packed. It is merely necessary that thearticle be already in a film bag which is closed on three sides and onthe end side of which, which is still open,

the side surfaces have already been folded inwards by a folding device.The article which is thus partially wrapped is fed on a conveyor belt 1to the heat-sealing and closing device. The heat-sealing device, in theembodiment shown, consists of two heat-sealing jaws 2 and 3; which aremovable towards each other, one of the heat-sealing jaws, the jaw 2, isheated. On the side of the heat-sealing jaws 2 and 3 facing away fromthe article to be packed there are located pulling rollers 4 and 5,which together form a pair. The lower pulling roller 4 is fixed on thelower heat-sealing jaw 3 and movable together with it. The secondpulling roller, the upper pulling roller 5, is driven by an electricmotor 6 and transmits the drive movement in the adjoining condition ofthe pulling rollers 4 and 5 via gears 7 (FIGS. 1 and 4) arranged atleast at one end of the pulling rollers. A guide ledge 8 arranged in thedirection of the conveyor belt 1 secs to it that the fold of the sideparts of the film remains intact. While the lower pulling roller 4 isfirmly connected to the heat-sealing jaw 3, the second pulling roller 5is arranged on a swivel device 9, which in its turn is rigidly connectedwith the stand of the heat-sealing device.

FIGS. 1 to 3 show a film bag fed on the conveyor belt 1 directly beforeits final heat-sealing. The parts of the film which protrude on one sideextend between the heat-sealing jaws and between the pulling rollers. Atthis time, the lower heat-sealing jaw 3 and the pulling roller 4 coupledwith it move up into their working position in the heat-sealing plane,and at the same time the upper pulling roller 5 swings downwardly in thedirection of the heat-sealing plane. The pulling rollers 4 and 5 therebycome into mutual engagement and pull the film closely past by thearticle 10 which rests against the ledge 8, this continuing until thepulling force, which has been set, is reached. This is shown in FIGS. 4to 6.

The upper, heated heat-sealing jaw 2 now enters into action, by movingin the direction towards the heatsealing plane and pressing against theunheated heatsealing jaw 3 which is already in its operating position.While the heat-sealing now takes place under the pressure of theheat-sealing jaws 2 and 3, the pulling roller 5 can move back into itsposition of rest, as shown in FIGS. 7 to 9.

The pulling rollers 4 and 5 are provided with a covering, which has asufficiently high coefficient of static friction with respect to thefilm to grip the film reliably and dependably. When packaging very heavyarticles as in the present example the lower pulling roller 4 has acovering, which has a higher coefficient of friction than the coveringof the upper pulling roller 5. Finally, it may also be pointed out that,depending on the nature of the heat-sealing device, the heat-sealing cantake place as long as the pulling rollers are in engagement or elseafter they have moved again away from each other. The first methodresults in very tight packages, but makes it necessary to have aheat-sealing device, which very firmly clamps the film during theheat-sealing and takes up the film tension coming from the pullingrollers. Furthermore, the heat-sealing must cool down sufficientlybefore the clamp opens. Accordingly in most cases it is sufficient forthe heat-sealing to take place after the pulling rollers have moved awayfrom each other again.

Last but not least, it is self-evident, that the embodiment describedand shown constitutes merely one example of the inventive concept andrather numerous other solutions are also possible. Thus, for instance,the pulling rollers could also be replaced by pulling rolls possibly aplurality of them arranged in a row. Instead of the gears for thecoupling of the pulling rollers for rotation with respect to each other,a friction drive could be used in which the friction disks have contactwith each other, when the pulling rollers contact each other.

I claim:

1. An apparatus for the tightening of a film package and the sealing ofa side of the package enclosing an article on at least three sides andhaving a projecting flap on the side to be closed, said apparatuscomprising:

a heat scaling device including a support,

a first heat sealing bar mounted on said support for movementperpendicular to the longitudinal dimension of said bar,

a further bar cooperating with said heat sealing bar to clamp said flapbetween said bars, and

means for heat sealing said flap upon the clamping thereof between saidbars and consituted by heating means on at least one of said bars; and

a pulling device engageable with said flap for drawing the film of saidpackage tightly around said article, said device including a firstpulling roller mounted on said first bar for movement therewith,

a second pulling roller on said support copperating with said pullingroller to grip said flap between said rollers,

a swinging mechanism pivotally mounting said second roller on saidsupport for movement toward and away from said first pulling roller,

an electric motor operatively connected to one of said pulling rollersfor driving same, and

a respective gear on one side of each pulling roller and'connectedthereto, said gears meshing upon swinging movement of said secondpulling roller toward said first pulling roller.

2. The apparatus defined in claim 1 wherein both of said rollers aredisposed to a side of said bars facing away from said article.

3. The apparatus defined in claim 2, further comprising a retainingledge engageable with said package and overlain by said flap forretaining said package against entrainment upon rotation of said pullingrollers.

4. The apparatus defined in claim 3, further comprising a horizontalconveyor for transporting said package past said devices, said ledgerunning parallel to said conveyor.

5. The apparatus defined in claim 4 wherein one of said rollers has afilm-engaging surface with a higher coefficient of friction than thefilm-engaging surface of the other roller.

6. The apparatus defined in claim 4, further comprising means forlimiting the driving torque transmitted to

1. An apparatus for the tightening of a film package and the sealing ofa side of the package enclosing an article on at least three sides andhaving a projecting flap on the side to be closed, said apparatuscomprising: a heat sealing device including a support, a first heatsealing bar mounted on said support for movement perpendicular to thelongitudinal dimension of said bar, a further bar cooperating with saidheat sealing bar to clamp said flap between said bars, and means forheat sealing said flap upon the clamping thereof between said bars andconsituted by heating means on at least one of said bars; and a pullingdevice engageable with said flap for drawing the film of said packagetightly around said article, said device including a first pullingroller mounted on said first bar for movement therewith, a secondpulling roller on said support copperating with said pulling roller togrip said flap between said rollers, a swinging mechanism pivotallymounting said second roller on said support for movement toward and awayfrom said first pulling roller, an electric motor operatively connectedto one of said pulling rollers for driving same, and a respective gearon one side of each pulling roller and connected thereto, said gearsmeshing upon swinging movement of said second pulling roller toward saidfirst pulling roller.
 2. The apparatus defined in claim 1 wherein bothof said rollers are disposed to a side of said bars facing away fromsaid article.
 3. The apparatus defined in claim 2, further comprising aretaining ledge engageable with said package and overlain by said flapfor retaining said package against entrainment upon rotation of saidpulling rollers.
 4. The apparatus defined in claim 3, further comprisinga horizontal conveyor for transporting said package past said devices,said ledge running parallel to said conveyor.
 5. The apparatus definedin claim 4 wherein one of said rollers has a film-engaging surface witha higher coefficient of friction than the film-engaging surface of theother roller.
 6. The apparatus defined in claim 4, further comprisingmeans for limiting the driving torque transmitted to said rollers.